21. They worked _____ day and night without rest in order to finish the project by _____ date of July 4.
A. a; / B. /; / C. /; the D. the; /
22. Do you expect _____ to be the possibility that the plane will arrive on time?
A. that B. there C. one D. it
23I’m afraid we will have to work extra hours, because there are still some problems______.
A. remaining to settle B. to remain to be settled
C. remaining to be settled D. remain to settle
